1. Field
The present disclosure relates to an optical sensor for measuring a distance or location and a sensing method using the same, and more particularly, to an optical sensor capable of sensing a distance or location of an article in a more precise and accurate way by correcting the difference in radiance caused by the surface color of the article when the optical sensor detects the intensity of radiation of a measurement light irradiated to and reflected on a sensing region to measure the distance of the article, and a sensing method using the same.
2. Description of the Related Art
To measure an object or obstacle at a short distance, sensors, particularly sensors using an infrared (IR) lighting, for irradiating a measurement light to a sensing region and measuring a reflected light to determine the presence of an object or obstacle in the sensing region are commonly used in industry.
Recently, a technique of measuring a location of an article by obtaining an IR lighting image with an image photographing element has been developed.
In a method of sensing an object at a short distance by using the above technique, a certain amount of light is firstly irradiated to a sensing region by using a photometric light, then a returning light reflected on the object existing in the sensing region is filtered by an IR lighting filter, and then a lighting image is obtained by means of a photographing element. Subsequently, the obtained IR lighting image is analyzed to find a location of an object or obstacle existing in the sensing region.
However, this technique has a limit in that an accurate distance cannot be calculated since the radiant of the IR light is changed by the surface material or color of the object. For example, even though a red object and a blue object are located at the same distance from the sensor, the red object may be erroneously measured to be closer since a relatively greater radiant of the IR light is reflected on the red object.
Therefore, this technique has a limit in that a measurement distance has an error due to the difference in radiant of a measurement light according to the surface color of an object.